Cassini’s Fiery Farewell

September 15, 2017

One of my favourite space missions is the Cassini mission to Saturn named after Giovanni Domenico Cassini, an Italian astronomer who discovered 4 of Saturn’s moons and noted the division in rings of Saturn now called the Cassini Division. Launched on October 15th, 1997, the probe arrived at Saturn on June 30th, 2004. Since that time, the probe has studied features of the gas giant such as Saturn’s hexagon shaped cloud formations at its Northern Pole, the cryovolcanoes of Saturn’s Moon, Enceladus where liquid oceans may harbour life, landed the Huygens probe on Saturn’s moon, Titan where we saw images beneath Titan’s mysterious atmosphere for the first time, and sent back the some of the most incredible images of space that we’ve ever seen. Some of these images include Earth (below) as we photobombed Saturn’s rings.

Earth as a Pale Blue Dot in the Distance Through Saturn’s Rings Cr. Cassini NASA/JPL

Wow! That’s us, that Pale Blue Dot. This is one of my favourite pictures of all time, made possible by the Cassini probe. It shows us…well…us. For all our differences on our world, when we see the planet like this, all our differences become (literally) astronomically tiny and our similarities astronomically large. We all live on this little world floating through the cosmos.

Cassini was placed on an extension mission in 2010 where it made detailed observations of Saturn’s moons and seasonal changes on Titan. Titan is the only other place in the solar system that has climate patterns affected by liquid like Earth does (except liquid methane rather than water). This past April, Cassini entered into a phase of its mission called “The Grand Finale.” As the probe neared the end of its life, the Grand Finale placed Cassini on 22 “daring dives” that passed between Saturn and Saturn’s rings typically too dangerous to have attempted earlier in the probe’s life and which allowed for closer observations of the rings than ever before.

In just a few hours at the time of writing this, Cassini will plunge into Saturn’s atmosphere, consumed by the very planet it has orbited for 13 years. This fiery finale will prevent the probe from contaminating any of Saturn’s moons; crucial in the future search for life. The predicted loss of signal from Cassini is currently predicted for 7:55am EDT, September 15th but that may change due to contact and friction with Saturn’s atmosphere. (Cassini will have vaporized about 83 minutes before that time; the time it takes for the final radio signals to reach Earth)

So, all that to say: A probe we launched a billion kilometers into space twenty years ago to peer through the atmosphere of an alien moon, take photos of ice volcanoes, and fly through the rings of a gas giant is going to be consumed by the atmosphere of Saturn as a fireball. My mind is exploding.

Early in our Chasing Atlantis journey, we had the privilege of interviewing one of the engineer’s on the Cassini mission, Kevin Grazier. Kevin worked on the imaging subsystems such as Cassini’s visible light camera which brought us these incredible photos of Saturn and its moons. Kevin is also often tapped by screenwriters as a science advisor where Kevin has worked on shows like Battlestar Galactica and Defiance and movies like Gravity and he’s the author of Hollyweird Science: From Quantum Quirks to the Multiverse. Below is a clip from our interview with Kevin.